Concurrence and Discord measurements in a Kitaev type 1D Spin chain

We present the study of concurrence and quantum discord in the ground state of 1D spins. The spins have the nearest neighbor Kitaev type interaction with the external transverse magnetic field. The system with periodic boundary condition gives the translation symmetry which simplifies the study to pairwise concurrence and discord at the odd and the even pair of sites separately. The correlation measures do not depend on the direction of the external field. They show dependence on spin length in the smaller chain but saturate quickly. The concurrence and the discord show the peak structure in the critical region but their derivatives do not show pronounced singularity to trace the phase transition of the system. The discord quantifies the correlation better as it gives finite correlation in the region where concurrence goes to zero.
Reference:
Vimalesh Kumar Vimal and V. Subrahmanyam, Phys. Rev. A 98, 052303 (2018).